The present disclosure relates to a heat exchanger.
In general, a heat exchanger is a part that is used in a heat-exchanging cycle. The heat exchanger may serve as a condenser or evaporator to heat-exchange a refrigerant flowing therein with an external fluid.
The heat exchanger may be largely classified into a fin-and-tube type and a micro channel type according to a shape thereof. The fin-and-tube type heat exchanger includes a plurality of fins and a tube having a circular shape or shapes similar to the circular shape and passing through the plurality of fins. The micro channel type heat exchanger includes a plurality of flat tubes through which a refrigerant flows and fins disposed between the plurality of flat tubes. In all of the pin-and-tube type heat exchanger and the micro channel type heat exchanger, a refrigerant flowing into the tube or flat tubes is heat-exchanged with an external fluid. Also, the fins may increase a heat exchange area between the refrigerant flowing into the tube or flat tubes and the external fluid.
Referring to FIG. 16, the micro channel type heat exchanger 1 according to the related art includes headers 2 and 3 coupled to a plurality of flat tubes 4. Hereinafter, a heat exchanger 1 that serves as an evaporator will be described as an example.
The headers 2 and 3 are provided in plurality. The first header 2 of the plurality of headers 2 and 3 is coupled to one side of the plurality of flat tubes 4, and the second header 3 is coupled to the other side of the plurality of flat tubes 4. Also, a heatsink fin 5 for easily heat-exchanging a refrigerant with external air is disposed between the plurality of flat tubes 4.
The first header 2 includes a refrigerant inflow part through which the refrigerant is introduced into the heat exchanger 1 and a refrigerant discharge part 7 through which the refrigerant heat-exchanged within the heat exchanger 1 is discharged. Also, a baffle 8 for guiding a flow of the refrigerant is provided within the first and second headers 2 and 3. The flow of the refrigerant within the first or second header 2 or 3 may be guided into the flat tubes 4 by the baffle 8.
The refrigerant introduced into the heat exchanger 1 may have a two-phase state. On the other hand, the refrigerant just before being discharged from the heat exchanger 1 may be a gaseous refrigerant or a refrigerant having a very high dryness degree. Thus, a flow rate of refrigerant to be discharged from the heat exchanger 1 may be relatively greater than that of refrigerant to be introduced into the heat exchanger 1.
Thus, the refrigerant may be concentrated into an outlet-side of the heat exchanger at which a flow rate of the refrigerant is relatively high. Particularly, when the header coupled to at least one side of the flat tubes 4 is vertically disposed, the gravity may acts on the refrigerant within the header to concentrate the refrigerant into the flat tube disposed at a lower portion of the outlet-side of the heat exchanger.
Also, as shown in FIG. 17, liquid and gaseous refrigerants flowing into the header 3 are partitioned as separate layers. That is, a liquid layer 3a and a gaseous layer 3b within the header 3 may be partitioned vertically or horizontally.
Also, since the liquid layer 3a may be formed with a thick thickness along an inner surface of the header 3, the refrigerant may not be uniformly distributed into the flat tubes 4. In addition, the liquid refrigerant may be introduced into one flat tube of the plurality of flat tubes, and the gaseous refrigerant may be introduced into the other flat tube.
As a result, an amount of refrigerant flowing into one flat tube of the plurality of flat tubes may be different from that of refrigerant flowing into the other flat tube to reduce heat-exchange efficiency.